How did new scientific knowledge help the building of the Panama Canal? A. Fewer workers got sick from malaria and yellow fever.
B. Radios helped workers stay in touch with their families.
C. Better nutrition led to more work being done by laborers.
D. Airplanes were able to deliver supplies more quickly.

The correct answer is A!!

Explanation:

Fewer workers got sick from malaria and yellow fever.A canal in Central America would make it easier to reach the Pacific Ocean from the eastern coast of the United States.New scientific knowledge help the building of the Panama canal because there was a decrease of workers getting sick of malaria and yellow fever. It was Colonel Gorgas, the Chief Medical Officer, who have read about discoveries linking mosquitoes and malaria. Due to these readings, he succeed in eradicating the cause of the disease therefore a decrease in people getting sick.

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president carter called the victims of kidnapping "victims of terrorism and anarchy" and added that the united states was not going to give in to blackmail. in the united states, they see hostage-taking as an outrage on the part of the islamist movement that violated the principle of international law on the immunity and inviolability of diplomats and their embassies.

carter refused to yield to the demands, khomeini used the situation to consolidate his power and nullify the challenges of the moderate wing of his government, headed by its president. the euphoria over the humiliation of the most powerful nation distracted the iranian people from the economic difficulties of their country. carter, in april 1980, broke diplomatic relations with iran and imposed a trade embargo, except medicine and food. iranian funds in the us they were frozen and accounted for to compensate the hostages when they were released and to pay the demands of us companies against iran.

the years following the end of world war i were a period of deep social tensions, aggrevated by high wartime inflation. food prices more than doubled between 1915 and 1920; clothing costs more than tripled. a steel strike that began in chicago in 1919 became much more than a simple dispute between labor and management. the steel strike of 1919 became the focal point for profound social anxieties, especially fears of bolshevism.

organized labor had grown in strength during the course of the war. many unions won recognition and the 12-hour workday was abolished. an 8-hour days was instituted on war contract work and by 1919, half the country's workers had a 48-hour work week.

the war's end, however, was accompanied by labor turmoil, as labor demanded union recognition, shorter hours, and raises exceeding the inflation rate. over 4 million workers--one fifth of the nation's workforce--participated in strikes in 1919, including 365,000 steelworkers and 400,000 miners. the number of striking workers would not be matched until the depression year of 1937.

the year began with a general strike in seattle. police offers in boston went on strike, touching off several days of rioting and crime. but the most tumultuous strike took place in the steel industry. then some 350,000 steelworkers in 24 separate craft union went on strike as part of a drive by the american federation of labor to unionize the industry. from management's perspective, the steel strike represented the handiwork of radicals and professional labor agitators. the steel industry's leaders regarded the strike as a radical conspiracy to get the company to pay a 12-hour wage for eight hours' work. at a time when communists were seizing power in hungary and were staging a revolt in germany, and workers in italy were seizing factories, some industrialists feared that the steel strike was the first step toward overturning the industrial system.

the strike ended with the complete defeat of the unions. from labor's perspective, the corporations had triumphed through espionage, blacklists, and the denial of freedom of speech and assembly and through the complete unwillingness to recognize the right of collective bargaining with the workers' representatives.

during the 1920s, many of labor's gains during world war i and the progressive era were rolled back. membership in labor unions fell from 5 million to 3 million. the us supreme court outlawed picketing, overturned national child labor laws, and abolished minimum wage laws for women.